The Blues had placed the 36-year-old on waivers on Friday.
An All-Star for St. Louis last season, Legace has struggled this season, going 13-9-2 with a 3.12 goals-against average and .885 save percentage. He was replaced as the Blues' top goalie by Chris Mason.
Legace is 177-92-18-18, with a 2.38 GAA and .912 save percentage in his 10-year career.
The Blues recalled goalie Chris Holt from Peoria to be Mason's backup.